The present invention is directed to bicycle components and, more particularly, to a bicycle shock absorber wherein the shock absorber elements are formed as multilayered structures.
Cycling grows in popularity not only as a transportation means but, to a greater extent, as a mode of recreation. In addition, cycling is a popular competitive sport for professionals and amateurs. It is known that mountain and road bicycles are currently provided with front or rear suspensions to absorb shocks transmitted to the rider both on and off the road. Numerous structures, ranging from simple to complex, are used for such suspensions. For example, Japanese Unexamined Patent Application 9-290790 teaches an inexpensive bicycle suspension with a simple structure. This suspension comprises a cylindrical external member with a plurality of projections extending inwardly and an internal member mounted inside the external member and having a plurality of projections extending radially outwardly, wherein the plurality of projections extending from the external member radially face the plurality of projections extending from the internal member. Elastic members are mounted between the external member and the internal member and are compressionally deformed by the relative rotation of the two members. The external and internal members may be integrally linked to respective front and rear frame members of the bicycle, wherein the rear frame member is fixed to the side plates. Thus, the shocks acting on the rear frame from the road surface due to road irregularities or differences in level are absorbed by the elastic members.
The elasticity of the elastic members, which are made of urethane rubber or other elastic bodies, determines the suspension characteristics. Enhancing the elasticity of the elastic members, for example, yields soft suspension characteristics and allows mild shocks caused by fine irregularities to be absorbed. However, such elastic members cannot effectively absorb large shocks, thus resulting in "bottoming out" of the shock absorbing device and causing harsh shocks to be transmitted to the rider. Conversely, lowering the elasticity of the elastic members results in harder suspension characteristics. While such elastic members soften the blow of large shocks, they fail to absorb milder shocks. As a result, it is difficult to construct a shock absorbing device that can absorb both sever and mild shocks.